Cross-flow reactor and method

ABSTRACT

Gas-phase reactors and systems are disclosed. Exemplary reactors include a reaction chamber having a tapered height. Tapering the height of the reactor is thought to reduce a pressure drop along the flow of gasses through the reactor. Exemplary reactors can also include a spacer within a gap to control a flow of gas between a region and a reaction chamber.

FIELD OF DISCLOSURE

The present disclosure generally relates to gas-phase apparatus andmethods. More particularly, the disclosure relates to cross-flowreactors and components, systems including the reactors and components,and methods of using the reactors, components, and systems.

BACKGROUND OF THE DISCLOSURE

Gas-phase reactors, such as chemical vapor deposition (CVD) reactors,including, for example atomic layer deposition (ALD) reactors, can beused for a variety of applications, including forming layers on asubstrate surface. Such reactors can be used to deposit, etch, clean,and/or treat layers on a substrate to form semiconductor devices, flatpanel display devices, photovoltaic devices, microelectromechanicalsystems (MEMS), and the like.

A typical gas-phase reactor system includes a reactor including areaction chamber, one or more precursor gas sources fluidly coupled tothe reaction chamber, one or more carrier or purge gas sources fluidlycoupled to the reaction chamber, a gas distribution system to delivergases (e.g., the precursor gas(es) and/or carrier or purge gas(es)) to asurface of a substrate, and an exhaust source fluidly coupled to thereaction chamber.

Cross-flow reactors are a type of gas-phase reactor that areparticularly useful when fast throughput and/or fast purging of areaction chamber is desired—such as for ALD deposition. In cross-flowreactors, gasses generally enter a reaction chamber at one end of thereaction chamber, flow laterally across a substrate within the reactionchamber, and exit at a second end of the reaction chamber.

Reaction chambers of cross-flow reactors are typically relatively small,allowing rapid purging of the chamber. The small reaction chamber alsoincreases a probability that a precursor will react with the substratesurface.

However, because of the relatively small reaction chamber, cross-flowreactors tend to exhibit a pressure drop from the gas inlet side of thereaction chamber to the flow outlet side of the reaction chamber. Thepressure drop can be significant in cross-flow reactors having areaction chamber with a low vertical height and/or in reactors that havea reaction chamber with a long flow path between the gas inlet and theflow outlet. Absorption of a precursor and/or reaction of a reactant ona substrate surface is generally proportional to a pressure within thereaction chamber. Thus, the pressure drop within the reaction chambercan cause differences in adsorption/reaction rates along a surface of asubstrate—e.g., between a leading and training edge of thesubstrate—which in turn can lead to increased non-uniformity ofprocesses within the reaction chamber. Accordingly, improved reactorsand reaction chambers are desired.

Another problem associated with cross-flow reactors is non-uniform gasflow between the reaction chamber and, for example a lower orload/unload area within the reactor. Many reactors do not form acomplete seal between the reaction chamber and the load/unload area, butrather allow a controlled gas flow between the two areas. However, thepressure difference between the two areas of the reactor can differabout a perimeter of a substrate. The non-uniform pressure can, in turn,lead to backside and edge deposition on or reaction with the substrateand other problems. Accordingly, improved reactor designs withmore-uniform pressure difference between the reaction chamber andanother chamber within the reactor are desired.

SUMMARY OF THE DISCLOSURE

Various embodiments of the present disclosure provide improvedcross-flow reactors, components thereof, and systems including thereactors. The cross-flow reactors and systems are suitable for use in avariety of gas-phase processes, such as chemical vapor depositionprocesses (including plasma-enhanced chemical vapor depositionprocesses), gas-phase etching processes (including plasma-enhancedgas-phase etching processes), gas-phase cleaning (includingplasma-enhanced cleaning processes), and gas-phase treatment processes(including plasma-enhanced gas-phase treatment processes). As set forthin more detail below, exemplary reactors, systems and methods may beparticularly well suited for processes in which relatively short purgetimes of gases from a reaction chamber are desired—e.g., atomic layerdeposition processes.

In accordance with various embodiments of the disclosure, a gas-phasereactor includes a cross-flow reaction chamber comprising a tapered topsurface and a bottom surface comprising a portion of a base plate and aportion of a top surface of a susceptor, a gas diffuser coupled to aninlet of the reaction chamber, and an exhaust coupled to the outlet ofthe reaction chamber. In accordance with various aspects of theseembodiments, a distance between the tapered top surface and the topsurface of the susceptor and/or base plate is greater proximate theinlet relative to a distance between the tapered top surface and the topsurface of the susceptor and/or base plate at the outlet. In accordancewith other aspects, the distance between the tapered top surface and thetop surface of the susceptor and/or base plate is greater proximate theoutlet relative to a distance between the tapered top surface and thetop surface of the susceptor and/or base plate at the inlet. Inaccordance with further aspects, the tapered surface comprises alinearly tapered surface. A distance between the tapered top surface andthe top surface of the susceptor and/or base plate at or proximate theinlet can range between about 1 mm and about 10 mm. Similarly, adistance between the tapered top surface and the top surface of thesusceptor and/or base plate at or proximate the outlet can range betweenabout 1 mm and about 10 mm. Gas-phase reactors in accordance withfurther exemplary aspects can include at least one spacer, such as apin, between the susceptor and the base plate. Use of the spacerfacilitates consistent spacing between the susceptor and the base plate,while still allowing flow between a region, such as a load or transitionregion within the reactor, and the reaction chamber. In accordance withfurther embodiments, a gap between the susceptor and the baseplateincludes a vertical and/or horizontal gap section.

In accordance with additional embodiments of the disclosure, a gas-phasereactor, such as an atomic layer deposition (ALD) reactor, includes across-flow reaction chamber comprising a top surface, a side surface,and a bottom surface, wherein a distance between the top surface and thebottom surface tapers from an inlet of the reaction chamber to an outletof the reaction chamber, a gas diffuser coupled to the inlet, and anexhaust coupled to the outlet. The distance between the top surface andthe bottom surface tapers, such that the distant between the top surfaceand the bottom surface increases from the inlet to the outlet ordecreases from the inlet to the outlet. In accordance with variousaspects of these embodiments, the gas-phase reactor includes a gapbetween the susceptor and the base plate. The gap can include one ormore horizontal and/or vertical gap sections. In accordance with furtheraspects, the gas-phase reactor includes a spacer, such as a pin, betweenthe susceptor and the base plate. In accordance with further exemplaryembodiments, the top surface is tapered—e.g., linearly.

In accordance with yet further exemplary embodiments of the disclosure,a gas-phase reactor system includes a gas-phase reactor as describedherein. For example, exemplary systems include a gas-phase reactorcomprising a cross-flow reaction chamber, wherein a vertical height(e.g., distance between a top surface and a bottom surface) of thereaction chamber is tapered (either increasingly or decreasingly) froman inlet to an outlet. In accordance with various aspects of theseembodiments, the system also includes a lower chamber and a gap betweenthe reaction chamber and the lower chamber. The system can include aspacer, such as a pin, to provide a desired vertical and/or horizontalgap between the reaction chamber and the lower chamber.

Both the foregoing summary and the following detailed description areexemplary and explanatory only and are not restrictive of the disclosureor the claimed invention.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

A more complete understanding of exemplary embodiments of the presentdisclosure can be derived by referring to the detailed description andclaims when considered in connection with the following illustrativefigures.

FIG. 1 illustrates a portion of gas-phase reactor system in accordancewith exemplary embodiments of the disclosure.

FIG. 2 illustrates a cut-away view of a portion of a gas-phase reactorsystem in accordance with exemplary embodiments of the disclosure.

FIG. 3 illustrates a close-up view of a portion of a reaction chamber inaccordance with exemplary embodiments of the disclosure.

FIG. 4 illustrates a further close-up view of the portion of thereaction chamber, illustrating a spacer, a portion of a susceptor, and aportion of a base plate in accordance with further exemplary embodimentsof the disclosure.

FIG. 5 illustrates a gap between a susceptor and a base plate, the gapincluding a horizontal gap section and a vertical gap section, inaccordance with additional exemplary embodiments of the disclosure.

FIG. 6 illustrates another exemplary gap between a susceptor and baseplate in accordance with yet additional exemplary embodiments of thedisclosure.

FIG. 7 illustrates another exemplary gap between a susceptor and baseplate in accordance with yet additional exemplary embodiments of thedisclosure.

FIG. 8 illustrates another exemplary gap between a susceptor and baseplate in accordance with yet additional exemplary embodiments of thedisclosure.

It will be appreciated that elements in the figures are illustrated forsimplicity and clarity and have not necessarily been drawn to scale. Forexample, the dimensions of some of the elements in the figures may beexaggerated relative to other elements to help to improve theunderstanding of illustrated embodiments of the present disclosure.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS OF THE DISCLOSURE

The description of exemplary embodiments provided below is merelyexemplary and is intended for purposes of illustration only; thefollowing description is not intended to limit the scope of thedisclosure or the claims. Moreover, recitation of multiple embodimentshaving stated features is not intended to exclude other embodimentshaving additional features or other embodiments incorporating differentcombinations of the stated features.

As set forth in more detail below, various embodiments of the disclosurerelate to gas-phase reactors and reactor systems that include avariable-height reaction chamber and/or a spacer to help define a gapbetween a susceptor and a base plate of the reactor.

FIGS. 1-5 illustrate portions or sections of a gas-phase reactor system100 in accordance with exemplary embodiments of the disclosure. System100 includes a reactor 202, including a reaction chamber 204, asusceptor 206, a diffuser 208, a mixer 102, a reaction chamber exhaustconduit 104, and a region 210, sometimes referred to herein as a lowerchamber or a load/unload area. Although not illustrated, system 100 mayadditionally include various gas sources, such as purge and reactant gassources, one or more exhaust and/or vacuum sources, and/or one or moreof a direct and/or remote plasma and/or thermal excitation apparatus forone or more reactants.

Reactor 202 may be used to deposit material onto a surface of asubstrate, etch material from a surface of substrate, clean a surface ofsubstrate, treat a surface of substrate, deposit material onto a surfacewithin reaction chamber, clean a surface within reaction chamber, etch asurface within reaction chamber, and/or treat a surface within reactionchamber 204. Reactor 202 can be a standalone reactor or part of acluster tool. Further, reactor 202 can be dedicated to deposition, etch,clean, or treatment processes, or reactor 202 may be used for multipleprocesses—e.g., for any combination of deposition, etch, clean, andtreatment processes. By way of examples, reactor 202 may include areactor typically used for chemical vapor deposition (CVD) processes,such as atomic layer deposition (ALD) processes.

Reaction chamber 204 is a cross-flow reaction chamber. During operation,gases enter reaction chamber 204 via diffuser 208 and flow horizontallythrough reaction chamber 204 to exhaust conduit 104. Typical cross-flowreaction chambers have a substantially constant height between a topsurface of the reaction chamber and a bottom surface of the reactionchamber (e.g., a top surface of susceptor 206). As noted above, suchdesigns can lead to significant pressure drop in the direction of gasflow across the reaction chamber, which in turn often leads tononuniform etching, cleaning, deposition, and/or treatment of a surfaceof a substrate within the reaction chamber.

In accordance with exemplary embodiments of the disclosure, reactionchamber 204 includes a tapered distance (or height) between a topsurface of the reaction chamber 212 (also referred to herein as atapered top surface) and a top surface of the susceptor 214 and/or abase plate 308. Reaction chamber 204 also includes a side surface 217.Initially, the inventors thought that tapering the distance from smallto large from an inlet 216 to an outlet 218 would work best to reducethe pressure drop across the reaction chamber. However, the inventorssurprisingly found that decreasing the vertical distance between topsurface of the reaction chamber 212 and top surface of susceptor 214and/or base plate 308 better reduced the pressure difference along theflow path of the reaction chamber. That said, both increasing anddecreasing distance between the top surface of the reaction chamber 212and top surface of susceptor 214 and/or base plate 308 reduced thepressure drop along the flow path of gasses through reaction chamber 204and resulted in more uniform processing of substrates within reactionchamber 204.

In accordance with exemplary embodiments of the disclosure, a distance(H3) between top surface of the reaction chamber 212 and top surface ofsusceptor 214 and/or base plate 308 at inlet 216 is between about 1 mmand about 10 mm, about 2 mm and about 8 mm, or about 2.5 mm and about7.5 mm. In accordance with further embodiments, a distance (H4) betweentop surface of the reaction chamber 212 and top surface of susceptor 214and/or base plate 308 at outlet 218 is between about 1 mm and about 10mm, about 2 mm and about 8 mm, or about 2.5 mm and about 7.5 mm. By wayof particular examples, a distance between top surface of the reactionchamber 212 and top surface of susceptor 214 and/or base plate 308 atinlet 216 is 7.5 mm and a distance between top surface of the reactionchamber 212 and top surface of susceptor 214 and/or base plate 308 atoutlet 218 is 2.5 mm. By way of other examples, a distance between topsurface of the reaction chamber 212 and top surface of susceptor 214and/or base plate 308 at inlet 216 is 2.5 mm and a distance between topsurface of the reaction chamber 212 and top surface of susceptor 214and/or base plate 308 at outlet 218 is 7.5 mm.

The height difference between top surface of the reaction chamber 212and top surface of susceptor 214 and/or base plate 308 can be linearlytapered. Alternatively, the tapered difference in height can be curved.Further, one or more of top surface of the reaction chamber 212, topsurface of susceptor 214 and the top surface of base plate 308 can betapered. By way of example, susceptor 206 and base plate 308 arehorizontally linear and top surface of reaction chamber 212 tapers(e.g., linearly) from inlet 216 to outlet 218.

Susceptor 206 is designed to hold a substrate or workpiece (notillustrated) in place during processing. In accordance with someexemplary embodiments, reactor 202 includes a direct plasma apparatus;in this case susceptor 206 can form part of a direct plasma circuit.Additionally or alternatively, susceptor 206 can be heated, cooled, orbe at ambient process temperature during processing. By way of example,susceptor can be heated during substrate processing, such that reactor202 is operated in a cold-wall, hot-substrate configuration.

In accordance with exemplary embodiments of the disclosure, reactor 202includes a gap, generally indicated as 300 in FIG. 3, between base plate308 of a reaction chamber and susceptor 206. Gap 300 is configured toallow some gas flow between region 210 and reaction chamber 204 duringsubstrate processing. Such a configuration can reduce undesiredreactions with a back surface of a substrate.

In the illustrated example, gap 300 includes a horizontal section 302, afirst vertical section 304, and a second vertical section 306.Horizontal section 302 can have a length, illustrated as L1, illustratedin FIG. 5, between about 2 mm and 20 mm, about 5 mm and 15 mm, or about7.5 mm and 12.5 mm. A distance between base plate 308 and susceptor 206,illustrated as D1, along L1 can range from about 0.001 to about 0.5 mm,about 0.01 to about 0.25 mm, or about 0.05 to about 0.2 mm, or be about0.1 mm. Vertical section 304 can have a length, illustrated as H1 inFIG. 3, between about 2 mm and 20 mm, about 5 mm and 15 mm, or about 7.5mm and 12.5 mm. A distance between base plate 308 and susceptor 206,illustrated as D2, along H1 can range from about 0.001 to about 0.5 mm,about 0.01 to about 0.25 mm, or about 0.05 to about 0.2 mm, or be about0.1 mm. Similarly, vertical section 306 can have a length, illustratedas H2, between about 2 mm and 20 mm, about 5 mm and 15 mm, or about 7.5mm and 12.5 mm. A distance between base plate 308 and susceptor 206,illustrated as D3, along H2 can range from about 0.001 to about 0.5 mm,about 0.01 to about 0.25 mm, or about 0.05 to about 0.2 mm, or be about0.1 mm.

Exemplary reactor 202 can include one or more spacers 402 to, forexample, facilitate consistently obtaining a desired spacing betweensusceptor 206 and baseplate 308. By way of examples, reactor 202includes between 1 and 10, 2 and 8, or about 3 spacers 402. Spacer 402can be formed of any suitable material, such as titanium, stainlesssteel, or the like.

In the illustrated examples, spacer 402 is a (e.g., threaded) pin. Inthe case of a threaded pin, a height of a pin (e.g., a distance a top404 of spacer 402 extends beyond a surface 406 of susceptor 206) can bemanipulated—e.g., by screwing or unscrewing spacer 402.

In the illustrated examples, spacer 402 includes a head section 310 anda threaded section 312. Head section 310 may not be threaded and/or maybe configured to receive a tool to enable manipulation of spacer 402relative to susceptor 206. Head section 310 can reside within a via 314of susceptor 206. Threaded section 312 can be threadedly received withina threaded via 316 within susceptor 206. Alternatively, spacer 402 canbe attached in the same or a similar fashion to base plate 308 toprovide desired spacing between base plate 308 and susceptor 206.

In accordance with some exemplary embodiments of the disclosure, baseplate 308 includes a recess 602 to receive a portion of spacer 402(e.g., a portion of head section 410). In these cases, susceptor 206 canbe rotated to align spacer(s) 402 with recess(es) 602 to allow susceptor206 to be in direct contact with base plate 308. This configuration maybe useful for leak testing or for performing other checks or maintenanceon reactor 202. Susceptor 206 can then be rotated to a processingposition, such as the position illustrated in FIG. 5, prior to or duringprocessing a substrate within reactor 202.

FIGS. 7 and 8 illustrate a portion of a reaction chamber 700 and aspacer 702 in accordance with additional exemplary embodiments of thedisclosure. Spacer 702 is similar to spacer 402, except spacer 702includes a recess area 704. Recess area 704 can be used to receive a setscrew to set a desired height of spacer 402.

FIGS. 7 and 8 also illustrate a serpentine gap 706 between a susceptor708 and base plate 710. Serpentine gap 706 includes a first segment 712,a second segment 714, a third segment 716, a fourth segment 718, and afifth segment 720. The dimensions of segments 712, 718, and 720 can bethe same or similar to the dimension of H1, D2, L1, D2, and H2, D3described above. The height of second segment 714 can range from about ¼to about ½ the height of first segment 712 with the same width, andthird segment 716 have a height about ¼ to about ½ the height of firstsegment 712 with the same width.

Although exemplary embodiments of the present disclosure are set forthherein, it should be appreciated that the disclosure is not so limited.For example, although the reactors and systems are described inconnection with various specific configurations, the disclosure is notnecessarily limited to these examples. Various modifications,variations, and enhancements of the exemplary systems and methods setforth herein may be made without departing from the spirit and scope ofthe present disclosure.

Unless otherwise noted, the subject matter of the present disclosureincludes all novel and nonobvious combinations and subcombinations ofthe various systems, components, and configurations, and other features,functions, acts, and/or properties disclosed herein, as well as any andall equivalents thereof.

What is claimed is:
 1. A gas-phase reactor comprising: a susceptorconfigured to hold a substrate during processing; a cross-flow reactionchamber comprising a tapered top surface and a bottom surface comprisinga portion of a base plate and top surface of the susceptor; a gasdiffuser coupled to an inlet of the reaction chamber; an exhaust conduitcoupled to the outlet of the reaction chamber; and a gap formed betweenthe reaction chamber and a lower chamber and between the base plate andthe susceptor, the gap comprising a vertical gap section and a pluralityof horizontal gap sections.
 2. The gas-phase reactor of claim 1, whereina distance between the tapered top surface and the bottom surface isgreater proximate the inlet relative to a distance between the taperedtop surface and the bottom surface at the outlet.
 3. The gas-phasereactor of claim 1, wherein a distance between the tapered top surfaceand the bottom surface is greater proximate the outlet relative to adistance between the tapered top surface and the bottom-surface at theinlet.
 4. The gas-phase reactor of claim 1, wherein the tapered surfacecomprises a linearly tapered surface.
 5. The gas-phase reactor of claim1, wherein a distance between the tapered top surface and the bottomsurface proximate the inlet ranges between about 1 mm and about 10 mm.6. The gas-phase reactor of claim 1, wherein a distance between thetapered top surface and the bottom surface proximate the outlet rangesbetween about 1 mm and about 10 mm.
 7. The gas-phase reactor of claim 1,further comprising at least one spacer between the susceptor and thebase plate, wherein a portion of the at least one spacer resides withinthe susceptor.
 8. The gas-phase reactor of claim 7, wherein the at leastone spacer comprises a pin.
 9. The gas-phase reactor of claim 1, furthercomprising another vertical gap section between the susceptor and thebase plate.
 10. The gas-phase reactor of claim 9, further comprisinganother horizontal gap section between the susceptor and the base plate.11. A gas-phase reactor comprising: a cross-flow reaction chambercomprising a top surface, a side surface, and a bottom surface, whereina distance between the top surface and the bottom surface tapers from aninlet of the reaction chamber to an outlet of the reaction chamber; agas diffuser coupled to the inlet; an exhaust coupled to the outlet; agap between the cross-flow reaction chamber and a susceptor configuredto allow gas flow between the cross-flow reaction chamber and a lowerchamber during substrate processing; and a spacer defining a portion ofthe gap.
 12. The gas-phase reactor of claim 11, wherein the gas-phasereactor comprises an atomic layer deposition reactor.
 13. The gas-phasereactor of claim 11, wherein the bottom surface comprises a portion of atop surface of a susceptor and a portion of a base plate.
 14. Thegas-phase reactor of claim 13, wherein the gap comprises a horizontalgap section and a vertical gap section between the susceptor and thebase plate.
 15. The gas-phase reactor of claim 14, wherein the gapfurther comprises another vertical gap section and another horizontalgap section between the susceptor and the base plate.
 16. The gas-phasereactor of claim 11, wherein the gap comprises a plurality of horizontalgap sections.
 17. The gas-phase reactor of claim 11, wherein the topsurface is tapered.
 18. The gas-phase reactor of claim 11, wherein adistance between the tapered top surface and the bottom surface isgreater proximate the inlet relative to a distance between the taperedtop surface and bottom surface at the outlet.
 19. The gas-phase reactorof claim 11, wherein a distance between the tapered top surface andbottom surface is greater proximate the outlet relative to a distancebetween the tapered top surface and the bottom surface at the inlet. 20.A gas-phase reactor system comprising: a gas-phase reactor comprising across-flow reaction chamber, wherein a vertical height of the reactionchamber is tapered from an inlet to an outlet; a lower chamber; a gapbetween the reaction chamber and the lower chamber, wherein the gapcomprises a plurality of horizontal gap sections and a plurality ofvertical gap sections; and a spacer defining a portion of the gap,wherein the susceptor and the base plate are in direct contact.
 21. Thegas-phase reactor of claim 20, further comprising another spacer todefine the gap.